Field of the Invention
The present invention relates to reaming frustoconical undercuts in cylindrical holes for placement of expansible bolts therein. More particularly, the invention relates to an improved, expansible rotary power tool for reaming frustoconical undercuts in cylindrical holes in flint and chert concrete using diamond impregnated cutters disposed on the leading edge of expandable cutter holding elements in such fashion as to maximize the surface area of the cutter being used.